Pilot-light controller



Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

EDWARD L. FONSECA, OF NEWARK, NEW JERSEY, ASSIGNOR TO THE WILCOLATOB. COMPANY, OF NEWARK, NEW JERSEY, A CORPORATION OF DELAWARE.

Pinon-men's. coN'rnoLLna.

Application filed August 20, 1926. Serial No. 180,430.

This invention relates to thermostatic devices for controlling the supply of fuel to a main burner in accordance with temperature conditions prevailing in proximity to a pilot burner for the main burner. More specifically, the invention is concerned with the provision of a pilot burner of improved construction to be used in association with a thermostatic controller, which is less subject to accidental extinguishment than the pilot burners heretofore used.

In my copending application, Ser. No. 89,641, filed February'QO, 1926, there is described a pilot burner control mechanism to be used in connection with a main heating burner. In this system, the flow of fuel to the main burner is controlled in accordance with the temperature generated in an oven chamber, for example, by the main burner, and when this temperature exceeds a predetermined value, the main burner is extinguished by the automatic closing of a fuel valve. lVhen'the temperature falls below the selected value, the fuel valve is opened, and the main burner is lighted by a continuously burning pilot placed in proximity to it. If the pilot burner should be extinguished accldentally at any time while the main burner is likewise extinguished, and thereafter fuel should'be supplied to the main burner, the escape of fuel from the main burner would lead to serious consequences. Accordingly, the system of the copending application includes a thermostatic device exposed to the temperature generated by the pilot burner and operable, when the pilot burner is not burning, toclose a valve controlling the main burner fuel supply.

In that application, the pilot burner used comprises a tube having a track of flame orifices leading to a point near the main burner.

The element is responsive to the temperature generated by the pilot flames but is out of the zone of temperature developed by the main burner. While that pilot burner is satisfactory. for general purposes, it is subject to extinguishment under certain conditions and while this immediately results in the fuel supply to the main burner being cut ofi so 50 that no considerable amounts of fuel escape,

still the extinguishment of the pilot requires that the attendant relight it and sometimes this causes inconvenience. Also inattention on the part of the attendant may result in the main heater burner being accidentally put out of operation for indefinite periods.

The object of the present invention, accordingly, is to provide a pilot burner for use In a system of the kind above described, which gives superior results due to its novel construction which prevents ready extinguishment. This burner is also arranged and constructed so that the thermostatic device used'in association with it may be placed well out of the 'zone of temperature of the main burner and is still extremely sensitive to the temperature at the pilot burner, receiving heat therefrom conductively rather than -by radiation. The new burner is capable of use with main burners either of the horizontal or vertical type, is readily installed, easily kept clean, and quickly dismantled, should occasion arise.

In its preferred embodiment, the pilo burner of the present invention comprises a tube connected to a fuel supply line in any convenient way and having a cap removably mounted on its end. This cap is provided with a plurality of tips extending outwardly therefrom, preferably in acircumferential row, these tips receiving fuel through the cap from the tube and lying near the main burner, so that the flames issuing therefrom will ignite the latter. Secured to the cap is a shield lying a short distance above the tips and having a part which lies partially in the path of the flames issuing from the tips. The i tance from the tips and the temperature re sponsive element receives heat from the shield and tips by conduction. As the tips extend in 'diflerent directions from the cap, an ordinary draft is unlikely to extinguish more than one or two'of the tip flames at any time. but if one tip should be extinguished, the fuel escaping from it is in part intercepted by the shield, accumulates thereunder, and is ignited by the tips still burning, thus relighting the extinguished tip. With this arrangement, the burner can be completely extinguished only with the greatest diificulty and will burn uninterruptedly for indefinite pe riods. i

For a better understanding of the invention, reference may be had to the accompany ing drawings, in which I Fig. 1 is a vertical sectional view of one embodiment of the invention,

Fig. 2 is a view in side elevation of a portion of the pilot burner,

Fig. 3 is a sectional view on the line 33 of Fig. 2,

Fig. 4 is a view of an inverted type partly in vertical section,

Figs. 5, 6 and '7 are sectional views illustrating the sequence of operations in the construction of a burner tip, and

Figs. 8 and 9 are side elevational views partly in section, showing the thermostatic control mechanism installed.

\Vith reference now to the drawings, the control mechanism includes a valve 10 connected in the fuel supply main 11 leading to a main heating burner 12. In this main is placed the usual shut-ott' valve 13 and a thermostatically controlled valve 14 which is operated by an element exposed to the temperature generated by the main burner. In the installation shown in Figs. 8 and 9, the main burner heats an oven or a vessel 15 and the thermostatic element which controls the valve 14 is within this chamber. The valve 1 1 is opened when the temperature within the chamber 15 falls below a selected value and closed when this or another selected value is exceeded.

- The valve 10 consists of a casin 16 havin a partition 17 forming a seat for a ball 18. This ball is mounted on the end of a rod 19 which extends through an opening in the wall of the casing and lies within a housing 20. The housing 20 is in the form of a. tube threaded into a bushing 21, the external surface of which is in the form of a nut, the housing being held in place by a lock nut 22. The bushing 21 is threaded into another bushing 23 which is threaded into a boss in the wall of the valve casing 16 and a lock nut 24, bearing on the upper face of the bushing 23, locks the bushing 21 in place. Mounted on the upper end of the housing 20 is a tubular chamber 25 the end of which is closed by a cap 26 threaded or otherwise secured in place. WVithin the chamber 25 is a bowed thermostatic element 27 of any convenient'form, one end of this element being secured to the cap 26; Preferablythis element is in the form of a bi-metallio strip, the legs of which approach or move away from each other in accordance with temperature variations. The rod 19 is secured to the free end of the strip 27 in any convenient manner, as, for example, by passing through an openin in the end of the strip, the end of the rod carrying a washer28 above the strip and a Washer 29 below, the latter being held against the strip by a spring 30 encircling the rod and bearing at its lower end againsta collar 31. Projecting downwardly from the bushing 23 are lingers ii'orn'iing a guide for the ball at the lower cndof the rod.

\Vith this construction, when the pilot light is extinguished the free end of the thermostatic clemcnt moves down bearing against washer 29 and through the spring 30 cansing a downward movement of the rod 19 to seat the pawl 18 and shut off the flow of gas to the main burner. Vhcn the pilot light is lighted, the free end of the thermostatic element moves upwardly bearing against the fixed washer on the rod 19 and lifting the pawl 18 from its seat to permit the flow of gas to the main burner. The operation of the valve by the strip is positive in both directions. although the connection between the strip and the rod by which the rod is moved' downwardly is yielding. Consequently, after the ball is seated any further drop in temperature will cause the free end of the strip to COH'IPIGSS the spring 30 as the ball is forced more firmly against its scat. By thus employing a connection between the rod and strip which is not rigid in this direction of movement of the strip, injury to the latter is avoided. l Vhen it is desired to set the device for different temperatures: the lock nuts 22 and 24 may be loosened and the bushing 21, by means of its nut, may be raised and lowered,'thus adjusting the position of the ball with reference to the seat. The thread 33 on the lower end of the bushing 21 is quite fine so that a complete revolution of the housing causes an endwise movement of only a short distance. Accordingly, an exact adjustment of the valve opening can readily be obtained. It will be noted that of the interior of the housing and the several bushings, and accordingly there are no parts tlat wear and the opening and closing of the valve is not impeded due to binding. The housing and the tubular members 25 and 26 at its upper end are gas-tight and as the moving parts lie entirely within the housing and casingthere are no packed joints through which the escape of the gas might occur.

The pilot burner includes a. tube 34 supplied with gas througha line 35 connected to the main 11, preferably at a point in' front of the valve 14, and in the connections to the tube may be placed a length of pipe 36 which may be bent at any angle required, this length of pipe being connected between the burner and the main by means of suitable unions. The burner tube 34 is secured to the cap member 26 in any convenient manner, as, for instance, by means of a screw 37, and atits free end the tube ,34: is closed by cap 35 threaded in place-on the end of the tube. This cap has a passage36 and is provided with a circumferential row of tips 37 supplied with gas from the tube 34. These tips extend radially and are shown in this par ticular burner as being four in number. Secured to the end of the cap above the tips is a shield 38 held in place in any convenient way, as by ascrew 39. The shield extends beyond the ends of the tips and has a dependin flange-40 which lies partially in the path of the flames issuing from the tips. The tips may produce a yellow flame, or may be designed for blue flames. For this latter purpose, each tip has an upper and lower opening 41 and 42. through which air may be induced by the flow of gas to mingle with the s and produce the blue flame in the usua way.

\Vith this arrangement it will be seen that the shield is heated by its contact with the flames and the heat travels conductively through the cap and the tube 34 and thence to the cap 26, to which the thermostatic element is secured- Accordingly, the. thermostatic element may be disposed at a considerabledistance from the main heater burner. In any event, it may lie out of the zone of temperature generated by themain heater burner and at the same time the element is responsive to the heat generated by the pilot burner as itreceives heat therefrom by conduction 'through the metal. The radial-arrangement of thetips-and the depending flange on the shield assist in preventing the extinguishment of the pilot light. It is unlikely that a draft will, under ordinary circumstances, cause the extinguishment of more than two of the tips and as soon as this current of air dies down, a part of the gas escaping from the extinguished tips will be diverted under the shield by the flan e, will flow around the shield to the tips stillburning, and thus flame from the burning tips will be carried back to the tips which have been extinguished and will cause their reignition. The shield thus'serves the dual purpose of absorbing heat which is transmitted conductively to the thermostatic element and at the same time assists in relighting any tips whichhave been accidentally extinguishe -In the construction of the cap I have found that the -ips'ma-y be conveniently mounted in place in it in the manner illustrated in .Figs. 5. 6, and 7. Each face of the cap has an opening 43 through which gas is to be supplied to a tip 37. A channel 44 is cut in the face of the cap around the opening at a distance therefrom, and in the inner wall of each tip is formed a circumferential channel 45. The tip is now placed in the channel 44 in the position illustrated in Fig. 6, and then, by means of a suitable tool, the upper edge of the flange 46 defined by the channel 44 and the opening 43 is flared outwardly, as at 47, the upset metal entering the channel and thus locking the tip in place in the cap. This flaring of the metal at the end of the opening 43 results in a better distribution of the gas within 'yond the Wall to constitute the tip and prevents the accumulation of soot, which is likely to occur in the event that the tip is threaded in place in the opening.

In Fig. 8 the burner 12 is of the horizontal type, the main 11 being connected to it from beneath. In this event, the'pilot construction, as shown in Fig. 1, is employed, the valve 10 being disposed in the main a short distance from the upright tube 48 leading to the main burner. In the event that the horizontal type of burner is used, as shown at 49 in Fig. 9. the pilot is mounted horizontally and the burner tube provided with an elbow as at 50 in the lower end of which the inverted cap 51 (Fig. 4) is secured. This cap is in all material respects the same as that illustrated in Fig. 1, except that the tube extends through the shield to the tips which lie beneath it. The shield may readily be mounted in place by providing the cap with a tubular extension 52 which is threaded into the end of the tube 34. this extension passing through an opening in the shield so that the shield is held bet ween the cap and the tube.

' It will be seen that with the pilot burner of the construction herein described, the pilot may be placed in any convenient location required by the construction of the main burners with which it is associated. The pilot flames are not readily extinguished and if partially extinguished, are relighted by the shield. Furtlmrmore the. teu'iperature-responsive element may be disposed at a considerable distance from the pilot and well out of the zone of ten'iperature generated by the main burner, since the element receives heat conductively which is transmitted to the bur-n er tube by means of the shield. With the tips mounted in the cap of the pilot burner in the manner described, they cannot readily be detached or lost, and the operations of mounting he tips in place are less diflicult and may be iierformed at a lower labor charge than those involved in threading the tip and cap.

I claim:

1. A pilot burner comprising a tube, a plurality of tubular members mounted in the wall of a tube in communication with the interior thereof and projectin outwardly befliune tips, and a shield mounted on the tube in proximity to the tips, this shield having a portion lying partially in the path of the flame issuing from said tips.

2. A pilot burner comprising a tube, a plurality of openings therein, a plurality of tubular members mounted in the wall of the tube and projecting beyond the wall. each member being in registry with an opening to constitute a flame tip, and a shield mounted on the tube and overlying the tips. this shield having a portion lying partially in the path of the flames issuing from said tips.

. '3. A pilot burner comprising a tube, a plurality of openings therein, a plurality of tu- Hill YO HdThPTTTdstlmIQOfAIlQn flange secured bular members mounted in the wall of the tube and projectin beyond the wall, each tips, this shield having a portion lying par- 'tially in the path of the flames issuing from said tips.

4:. A pilot burner comprising a tube, a plurality of openings therein, a plurality of tu: bular members mounted in the wall of the tube and projecting beyond the wall, each member being in registry and constituting a flame tip, a shield mounted on the tube above the tips and extending beto the shield beyond the ends of thetips, the flange extending toward the tips and lying partially in the path of the flames issuing from the tips.

5. A pilot burner comprising a tube, a plu rality of openings in the tube arranged in a row extending around the tube, a plurality of tips, each mounted in the wall of the tube in registry with an opening and extending radially from the tube, a plate-like shield mounted on the tube above the row of tips and a flange secured to the shield and lying partially in the path of the flames issuing from the tips.

6. A pilot burner comprising a tube, a cap mounted on the end thereof, a plurality of tips mounted radially in the cap and in communication with the tube through the cap, a shield attached to the cap above the tips, and

from thetlps.

the upper wallof each tip for th of air,'a shieldsecured to the cap above the from the shield with an opening a flange depending from the shield and lying partially the path of the flames issuing 7. A pilot burner comprising a tube, a cap mounted on theend thereof, a plurality of tips mounted radially in tliecap in a plane transverse to the tube and in communication with the tube through the cap, an opening in e induction tips, and a' flange depending and lyin partially in the path of the flames issuing rom the tips. v

8. In a pilot burner, a cap for mounting on the end of a tube and having openings in the walls thereof, a channel formed in the body of the cap extending around and spaced from each opening, and a-tubular tip having' its end received in each. channel and having a recess extending around it and formed in its inner wall, a portion of the cap around the ope'ningb'eing upset into the recess to hold the tip in place. a e

9. In a pilot burner, a cap for mounting on the end of a tube and having openings in the walls thereof, these openings being defined in part by tubular flanges, a channel between the outer wall'of each flange and the body of the cap, a tubular tip fitted over each flange with its end entering the channel, and a circumferential recess in the inner wall of each tip, the end of the'flange being outwardly flared to enter the recess and lock the tip in position, this flaring increasing the diameter of the opening.

In testimony whereof I aflix my signature.

EDl/VARD L. FONSECA. 

